I put a 70 302 in my 65 custom 500 and I think this motor is on the edge of needing more then regular gas even though its a 2 bbl motor,does anyone know what the compression ratio is for this motor. It has less then 20,000 miles but I doubt it has hardened seats so I might be looking for a newer set of heads that have a slightly bigger combustion chamber and would like to know what ones to use that would flow similar to the 70 heads. When the compression was lowered in the early 70s was it in the heads or were dished pistons used,since this motor has low miles I really dont want to tear into it but it does have one lifter making noise from the 30 year storage so a change to a 4 bbl will happen when I replace the lifters but I am also thinking about changing the timing chain to get rid of the plastic cam gear that might come apart from age so I while the front of the motor is off I would like tp put in a little hotter cam and if I have it that much apart I might go ahead and put on a set of heads with hardened seats while I am in there. Jeff